Physical Activity and Sedentary Screen Time in Obese and Overweight Children Living in Different Environments.

AIM: To assess the relationship of children's physical activity and sedentary screen time with overweight and obesity in children living in different environments (town and city) in Lithuania. METHODS: An analysis of anthropometric data from 532 children living in town and city areas was performed. A youth physical activity questionnaire (YPAQ) was conducted to evaluate physical activity and sedentary screen time. RESULTS: The prevalence of overweight and obesity among the children was 25.5% in the town and 18.6% in the city. Children living in the town on average engaged 9.3 min/day less in moderate to vigorous physical activity (p=0.050) and had 33.2 MET-min/day lower energy expenditure than children living in the city. Sedentary screen time was extremely high on weekends in both town and city children. CONCLUSIONS: A higher prevalence of overweight and obesity and a lower amount of moderate-to-vigorous physical activity was found in children living in the town compared to children living in the city.

Research and assessment of safety distance of TV electromagnetic fields.

The evaluation covers the strengths of electric field and magnetic flux density measured in frequency ranges of 5 Hz-2 kHz and 2-400 kHz of selected TV sets. The dependence of the electromagnetic field on the distance is addressed with reference to ergonomics and safety. Ten TV sets (5 tube and 5 LCD) were measured. There were 16 measurements for each one. The aim was to evaluate electric field and magnetic flux density versus the distance from the tested device with regard to exposure levels. In addition, the distance and the strengths of electric field and magnetic flux density emitted by tube and LCD TVs were compared. The results are presented in charts.

A Technical Approach to the Evaluation of Radiofrequency Radiation Emissions from Mobile Telephony Base Stations.

During the last two decades, the number of macrocell mobile telephony base station antennas emitting radiofrequency (RF) electromagnetic radiation (EMR) in residential areas has increased significantly, and therefore much more attention is being paid to RF EMR and its effects on human health. Scientific field measurements of public exposure to RF EMR (specifically to radio frequency radiation) from macrocell mobile telephony base station antennas and RF electromagnetic field (EMF) intensity parameters in the environment are discussed in this article. The research methodology is applied according to the requirements of safety norms and Lithuanian Standards in English (LST EN). The article presents and analyses RF EMFs generated by mobile telephony base station antennas in areas accessible to the general public. Measurements of the RF electric field strength and RF EMF power density were conducted in the near- and far-fields of the mobile telephony base station antenna. Broadband and frequency-selective measurements were performed outside (on the roof and on the ground) and in a residential area. The tests performed on the roof in front of the mobile telephony base station antennas in the near-field revealed the presence of a dynamic energy interaction within the antenna electric field, which changes rapidly with distance. The RF EMF power density values on the ground at distances of 50, 100, 200, 300, 400, and 500 m from the base station are very low and are scattered within intervals of 0.002 to 0.05 µW/cm². The results were compared with international exposure guidelines (ICNIRP).

Modelling and assessment of the electric field strength caused by mobile phone to the human head.

BACKGROUND/AIM: Electromagnetic field exposure is the one of the most important physical agents that actively affects live organisms and environment. Active use of mobile phones influences the increase of electromagnetic field radiation. The aim of the study was to measure and assess the electric field strength caused by mobile phones to the human head. METHODS: In this paper the software "COMSOL Multiphysics" was used to establish the electric field strength created by mobile phones around the head. RESULTS: The second generation (2G) Global System for Mobile (GSM) phones that operate in the frequency band of 900 MHz and reach the power of 2 W have a stronger electric field than (2G) GSM mobile phones that operate in the higher frequency band of 1,800 MHz and reach the power up to 1 W during conversation. The third generation of (3G) UMTS smart phones that effectively use high (2,100 MHz) radio frequency band emit the smallest electric field strength values during conversation. The highest electric field strength created by mobile phones is around the ear, i.e. the mobile phone location. The strength of mobile phone electric field on the phantom head decreases exponentially while moving sidewards from the center of the effect zone (the ear), and constitutes 1-12% of the artificial head's surface. CONCLUSION: The highest electric field strength values of mobile phones are associated with their higher power, bigger specific energy absorption rate (SAR) and lower frequency of mobile phone. The stronger electric field emitted by the more powerful mobile phones takes a higher percentage of the head surface. The highest electric field strength created by mobile phones is distributed over the user's ear.

Physical activity and physical fitness in obese, overweight, and normal-weight children.

BACKGROUND/AIM: The aim was to assess the differences between physical activity and physical fitness in obese, overweight, and normal-weight children. MATERIALS AND METHODS: The cross-sectional study was accomplished using cluster sampling method at 3 Lithuanian schools. An analysis of anthropometric data for 532 Lithuanian children was performed. Height, weight, waist and hip circumferences, and skinfold thickness were measured. Body mass index, waist-to-hip ratio, and body fat percentage were calculated. The Youth Physical Activity Questionnaire and a 6-min walk test (6MWT) were administered to evaluate physical activity and physical fitness. Maximal oxygen consumption was calculated to assess the children's aerobic capacity. Correlations among anthropometric data, 6MWT-walked distance, and moderate-vigorous physical activity duration were analyzed. RESULTS: The study showed that 20.1% of the studied children were obese or overweight. They engaged in moderate-to-vigorous physical activity 22.4 min less per day and walked 50.9 m less on average during a 6-min test than normal-weight children. Physical fitness parameters correlated with daily moderate-vigorous physical activity duration and with most of the children's anthropometric parameters. CONCLUSION: Obese and overweight children were less physically active and had lower physical fitness than normal-weight children. The findings underline the need for interventions to increase physical activity and improve fitness in obese and overweight children.

The assessment of electromagnetic field radiation exposure for mobile phone users.

BACKGROUND/AIM: During recent years, the widespread use of mobile phones has resulted in increased human ex- posure to electromagnetic field radiation and to health risks. Increased usage of mobile phones at the close proximity raises questions and doubts in safety of mobile phone users. The aim of the study was to assess an electromagnetic field radiation exposure for mobile phone users by measuring electromagnetic field strength in different settings at the distance of 1 to 30 cm from the mobile user. METHODS: In this paper, the measurements of electric field strength exposure were conducted on different brand of mobile phones by the call-related factors: urban/rural area, indoor/outdoor setting and moving/stationary mode during calls. The different types of mobile phone were placed facing the field probe at 1 cm, 10 cm, 20 cm and 30 cm distance. RESULTS: The highest electric field strength was recorded for calls made in rural area (indoors) while the lowest electric field strength was recorded for calls made in urban area (outdoors). Calls made from a phone in a moving car gave a similar result like for indoor calls; however, calls made from a phone in a moving car exposed electric field strength two times more than that of calls in a standing (motionless) position. CONCLUSION: Electromagnetic field radiation depends on mobile phone power class and factors, like urban or rural area, outdoor or indoor, moving or motionless position, and the distance of the mobile phone from the phone user. It is recommended to keep a mobile phone in the safe distance of 10, 20 or 30 cm from the body (especially head) during the calls.